Messaging Proxy System

ABSTRACT

A messaging proxy system is disclosed for the purpose of delivering data in the form of a portable message format from a producer running on a mobile or non-mobile computer, over any wireless network, by passing this data through an intermediary proxy computer program, to one or more recipients running on mobile or non-mobile computers. The system includes a message proxy computer program with at least one pluggable transport protocol adapter. The proxy contains a command subsystem for sending and receiving command- and message-tokens to and from the mobile clients. The system further includes a thin messaging middleware client to run on mobile devices. The thin messaging middleware client includes at least one pluggable protocol adapter. The client also comprises a command subsystem for sending and receiving command- and message-tokens to and from the proxy. The proxy also contains a communication subsystem for sending and receiving messages via a state of the art message oriented middleware.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.10/824,200, filed on Apr. 13, 2004, which is a continuation of U.S.patent application Ser. No. 09/611,629, filed on Jul. 7, 2000, now U.S.Pat. No. 6,721,779, each of which is incorporated herein by referencefor all purposes.

FIELD OF THE INVENTION

The invention relates to techniques for the delivery of electronicmessages between hardware or software components across wireless andwireline networks, between mobile and non-mobile devices.

BACKGROUND OF THE INVENTION

Message oriented middleware (MOM) has been available for many years. InOctober 1998, an industry standard emerged from Sun Microsystems, theJava Message Service (JMS). At a programming interface level, thisstandard describes how a messaging middleware is accessed from a Javaapplication. The two main abstractions of JMS are “topics”(publish/subscribe messaging) and “queues” (point-to-point messaging).While the standard describes the interface to the messaging middleware,the implementation of the middleware is not specified. Also, integrationof wireless mobile devices (such as phones, pagers, personal digitalassistants or laptops) is not specified.

Existing messaging middleware allows one to access the middleware fromnon-mobile devices (personal computers or server computers) overwireline networks (Ethernet or Token Ring). These networks usually runcommunication protocols such as TCP/IP, HTTP or SSL. Supporting wirelessmobile devices requires the vendor of the middleware to implement amessage transmission protocol atop a wireless transport protocol (suchas WAP, GSM, SMS, GPRS, or UMTS) and to integrate this messagetransmission protocol into the middleware.

This leads to limited applicability for the following reasons:

-   State of the art JMS messaging middleware requires more computer    memory than is available on mobile devices.-   Mobile devices, which are often disconnected from a corporate    network, are unsupported in state of the art JMS messaging    middleware products.-   Wireless protocols such as WAP, SMS, GPRS or UMTS are not supported    by state of the art JMS messaging middleware products, unless the    TCP/IP, HTTP or SSL protocol is used atop those wireless protocols.-   Though state of the art JMS messaging middleware products support    communication protocols such as TCP/IP, HTTP, and SSL, they do not    support any other communication protocols.

Further, there are considerable performance impacts, as TCP, HTTP or SSLwere designed for wireline networks and thus do not perform well onwireless networks.

SUMMARY OF THE INVENTION

A first object of the invention is therefore to provide a system for thedelivery of data between applications serving as clients and running onmobile wireless devices and applications running on computers of a wirednetwork. Another object of the invention is to provide a method fordelivering data between an application serving as client and running ona mobile wireless device and an application running on a computer of awired network. Yet another object of the invention is to provide acomputer program loadable into the memory of a computer usable fordelivering messages between clients on mobile wireless devices andapplications running on computers. A further object of the invention isto provide a computer program product comprising a computer usablemedium having thereon computer readable program code means forimplementing on a computer connected to a wired computer network. Stillanother object of the invention is to provide a computer programdirectly loadable into the memory of a mobile device and allowing themobile device to access a messaging middleware product according to thestate of the art, without needing to load that messaging middleware intothe memory of the mobile device entirely.

The messaging proxy system outlined in this disclosure is a majortechnological advancement enabling users of state of the art messagingmiddleware products to send and receive messages to and from mobiledevices, over any wireless transport protocol, without requiring thatthe state of the art messaging middleware be loaded into the memory ofthe mobile devices.

The system for running said message proxy installation includes amessage proxy implemented by a computer program with a systemarchitecture comprising at least one pluggable protocol adapter. In apreferred embodiment of the invention, the proxy further comprises atleast one pluggable database adapter.

The invention also comprises a thin message client computer programdirectly loadable into the memory of a mobile device. This thin messageclient program allows a mobile device to exchange message and commandtokens with a message oriented middleware according to the state of theart, by using the proxy computer program as an intermediary between thethin client and the message oriented middleware and thereby using atleast one wireless transport protocol. The thin message client computerprogram embodies a system architecture of at least one pluggableprotocol adapter. Preferably, it also embodies a system architecture ofat least one pluggable database adapter.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, an example of an embodiment of the invention isdescribed with reference to drawings. In the drawings:

FIG. 1 provides a block diagram of a preferred embodiment of the systemaccording to the present invention, and

FIG. 2 shows a UML sequence diagram of an embodiment of the methodaccording to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now with reference to the drawing, FIG. 1 provides a block diagram of apreferred embodiment of the present invention. It more particularlyshows an installation of software tools loaded on non-mobile computersand mobile wireless devices, the installation comprising:

-   A message proxy 1,-   Thin JMS message clients 2, 2′, 2″ linked to the proxy 1 with a    wireless communication protocol,-   JMS message oriented middleware 3 according to the state of the art,    and-   A JMS message oriented middleware client 4.

The block diagram is but one example of a message proxy infrastructuredeployment. Any number of message proxies, thin JMS message clients,message oriented middleware products, and message oriented middlewareproduct clients can be present in a specific installation.

The message proxy 1 may be implemented on a conventional computernetwork server, e.g on a Windows-NT-server and may e.g. run in thebackground. It maintains client connections, maintains clientsubscriptions to JMS topics and queues, receives and forwards JMSmessages, and stores JMS messages in its database, such that they willnot be lost when a client is disconnected from the proxy.

The message proxy 1 comprises at least one pluggable transport protocoladapter. FIG. 1 shows an example of six specific wireless transportprotocol adapters (WAP 1 a, UMTS 1 b, HTTP 1 c, DAB/GSM Data 1 d, SMS 1e, GPRS 1 f). Any number of additional wireless protocol adapters 1 gcan be present. Pluggable protocol adapters allow the message proxy tosend and receive messages to and from message clients using arbitrarywireless protocols. A protocol adapter embodies an existing transportprotocol, such as GPRS or TCP/IP, and also provides additional featureson top of the existing transport protocol. Examples of such additionalfeatures include data encryption and guaranteed delivery of messages. Aprotocol adapter is divided into one or more protocol objects. Eachprotocol object provides one part of the functionality offered by theprotocol adapter. For example, a protocol object can encrypt data, orcompress data, or request the sender of the data to retransmit a messagewhich was lost on the network.

The message proxy 1 also comprises a database adapter. This allows theproxy to store messages and client subscription information intoarbitrary databases.

On startup, the message proxy 1 reads its configuration data andinitializes all configured protocol adapters. It also initializes thetopic and queue subscriptions of all the message clients which are knownto the proxy. At runtime, additional protocol adapters can be started,or running protocol adapters can be stopped, without interrupting themessage proxy service (however, if a specific protocol adapter isstopped, service over this adapter is no longer available). At runtime,additional clients can be connected to the proxy, or existing clientscan be disconnected from the proxy.

Each thin JMS message client 2, 2′, 2″ is installed on a mobile wirelessdevice such as a mobilephone, a small laptop computer with a wirelessmodem, a palmtop device or any other device comprising a processor, amemory and communication means for communicating wirelessly. It containsa JMS programming library which is identical or similar to at least apart of the programming library used by messaging middle 3 of the stateof the art. The thin JMS message client library is small enough to beloaded into the memory of the mobile devices which have constrainedmemory and processing power.

Such a small footprint of the thin JMS message client library isachieved by offloading from the client to the proxy most of thecomputations and most of the state information which a JMS clientapplication ought to perform or to maintain. The thin JMS message clientmainly consists of the JMS interface. Most of the Java code necessaryfor implementing the interface is running on the proxy, and not on thethin JMS message client. The proxy also maintains the JMS stateinformation associated with the client. For example, the proxy storesthe JMS messages which have not been acknowledged by the client yet.Also, the thin JMS message client does not need to store the names ofthe queues and topics it is subscribed to. This information is storedonly by the proxy. Internally, the thin JMS client uses codeinformation, such as number values, to refer to topics and queues. Thiscode information can be as small as one byte. The actual representationof those queues and topics, which can be hundreds or thousands of bytesfor each topic or queue, is contained in the proxy. When the thin JMSclient wishes to publish a message on a certain topic, the client sendsto the proxy only the JMS message and the code information related withthe topic. All this considerably reduces the footprint of the thin JMSclient.

The thin JMS message client 2 also contains a command and messagetransmission system comprising a transport protocol adapter 2 a, 2 a′, 2a″ used for informing the proxy of what JMS topics and queues the clientwants to subscribe to.

The message client 2, 2′, 2″ also comprises a database adapter. Thisallows the client to store JMS messages and other information locally,using arbitrary databases. The message database is necessary to ensurethat JMS messages and JMS subscriptions submitted by the client are notlost in case the client cannot communicate with the proxy due to lack ofwireless network coverage, or because the proxy is not running.

A message client 2, 2′, 2″ links to the message proxy 1, using itstransport protocol adapter 2 a, 2 a′, 2 a″. If a matching protocoladapter is running on the proxy, the connection is successful. Furthercommunication between message client and message proxy is according tothe familiar publish/subscribe or point-to-point model of JMS.

JMS topics or JMS queues are named and administered independently of theprotocol adapters involved. If a client connects to the proxy using the“WAP” protocol adapter, it can communicate with a client that connectedusing the “GPRS” protocol adapter, if both clients use the same JMStopic or queue.

The protocol adapters encapsulate at least one logic needed to:

-   Interface with a transport protocol, such as HTTP, WAP or GSM Data.-   Specify and guarantee a quality of service for the message delivery.

Certain transport protocols operate in a “best effort” delivery mode.Thus, simply adapting to a specific protocol is not always enough(unless “best effort” is the desired message delivery guarantee). Thus,protocol adapters consist of both the transport protocol mechanism, anda quality of service mechanism to improve the basic network deliveryguarantee.

Network reliability is improved as follows. The sending protocol adapterattaches a reliability indicator such as a sequence number to alloutgoing messages. The reliability indicator is varied in a predefinedmanner upon sending a message. E.g., the sequence number is incrementedby one after each sent message. The receiver application uses thereliability indicator of the incoming message to detect whether amessage was lost. In the described example, this is the case when thesequence number of the just received message is greater than thesequence number of the previous message, plus one. In the event ofmessage loss, the receiver sends a command token to the senderindicating which messages are to be retransmitted. The sender thenretransmits the requested messages. The sender keeps messages in a localdatabase to be able to fulfill a message retransmission request.

The database adapters encapsulate at least one logic needed to:

-   Interface with a database product, such as PointBase, Oracle, DB/2,    or Sybase, OR to interface with a portable database access software    such as JDBC or ODBC.-   Store and retrieve JMS messages and JMS subscription requests.

The message client 2 implements e.g. the JMS API from Sun Microsystems.It cooperates with the proxy to achieve full JMS functionality. When theclient wants to subscribe to a JMS queue or topic, its command subsystemcreates a command token containing the subscription information. Thecommand token is then sent to the proxy using wireless communication. Tothis end, the token is sent via a protocol adapter 2 a, 2 a′, 2 a″ atthe client side and received by a protocol adapter 1 a, 1 b, 1 c, 1 d, 1e , 1 f or 1 g at the proxy side.

On receipt of a command token, the proxy 1 reads the subscriptioninformation contained in the token, and performs a JMS subscription withthe state of the art middleware, on behalf of the client.

Further command tokens are generated when the client wants tounsubscribe from a JMS topic or queue, when the client wants to transmita JMS message, or for any other JMS action which is requested by theclient.

When a JMS message is received on a topic or queue the proxy 1 issubscribed to on behalf of the client, the proxy creates a message tokencontaining the data of the JMS message. The message token is then sentto the client 2 using wireless communication. For that the token is sentvia a protocol adapter 1 a, 1 b, 1 c, 1 d, 1 e , 1 f or 1 g at the proxyside, and received by the protocol adapter 2 a, 2 a′, 2 a″ at the clientside.

On receipt of such a message token by a thin JMS message client 2, a JMSmessage is created by the client. Then, the JMS message is processed bythe client. For example, the message can be visualized in a graphicaluser interface.

The JMS message oriented middleware 3 according to the state of the artcan be any JMS messaging middleware product, for example, IBM'sMQSeries, SoftWired's iBus, or Progress' SonicMQ.

The JMS message oriented middleware client 4 is a client applicationimplemented on a non-mobile computer, i.e. on a computer connected to awired computer network, using a state of the art JMS message orientedmiddleware 3. One or more JMS message oriented middleware clients 4according to the state of the art can be present.

For the describing an example of the communication between differentexamples, it is assumed that the thin JMS message client 2 is subscribedto a topic T. Such a topic T can, depending on the application, denote astream of stock quotes, of sports news, or denote a transmission channelcarrying digital audio. When a state of the art JMS message orientedmiddleware client 4 sends a JMS message to topic T, the message ispassed first to the state of, the art JMS message oriented middleware 3.The message will then be received by the proxy 1 on behalf of thinclient 2. Next, proxy 1 transmits the JMS message to client 2 in theform of a message token using one of its transport protocol adapters 1a, 1 b, 1 c, 1 d, 1 e, 1 f or 1 g. Finally, client 2 receives the JMSmessage on topic T as if it was accessing the state of the art JMSmessage oriented middieware 3 directly.

In order to show this procedure in more detail, in the following anexample of the method for delivering information between applicationsrunning on mobile wireless devices and serving as clients andapplications running on non-mobile computers is described with referenceto FIG. 2.

The sequence diagram of FIG. 2 shows the interactions—represented byarrows—occurring between a mobile client and a proxy during oneinformation exchange, namely during the creation of a JMS TopicPublisherfor a topic T by the mobile client and a subsequent publishing of amessage published on Topic T. In the diagram, the mobile client issymbolized by a shaded and dashed box. The vertical line on the righthand side of the figure represents the message proxy. The method stepsare denoted by numbers which are not to be confused with the referencenumerals of FIG. 1.

1. A JMS TopicPublisher object “Pub” is created, upon request of theapplication, for JMS publish/subscribe topic “T”. Later, “Pub” willallow the mobile client application to publish a JMS message on topic“T”.

2. The Thin Message Client Library creates a command token containingthe information which is needed by the proxy for allocating a JMSTopicPublisher, on behalf of the client. The command token contains acode information (e.g. a one-byte number) denoting a ‘Create apublisher’ command. It also contains the JMS topic “T” the publishershall be tied to (e.g. a one-byte number), as well as an informationCode “P” (e.g. a one-byte number) denoting the publisher.

3. The proxy creates a JMS TopicPublisher “Pub” for topic “T” on behalfof the thin client.

4. The proxy associates TopicPublisher “Pub” with the code information“P”. This can be done by storing the TopicPublisher “Pub” into a datadictionary, using code information “P” as the search key.

5. The client application creates a JMS message “msg” containingapplication specific information, e.g., a book order. This step, ofcourse, as well as the subsequent step 6, can be carried out followingto or simultaneously to steps 3 and 4.

6. The client application now publishes JMS message “msg” on topic “T”,using TopicPublisher “Pub”.

7. The Thin Message Client Library creates a command token containingthe information which is needed by the proxy for publishing the messageusing state-of-the-art JMS middleware. The command token contains a codeinformation (e.g. a one-byte number) denoting a ‘Do publish’ command. Italso contains the code information for the TopicPublisher (Code “P”) aswell as the message “msg”.

8. The proxy retrieves the TopicPublisher “Pub”, which is associatedwith Code “P”. This publisher “pub” was associated with Code “T” in Step4.

9. Finally, the proxy publishes the JMS message “msg” on topic “T” usinga state of the art JMS middleware. Concretely, the proxy forwards themessage “msg” on topic “T” to a state of the art JMS application usingJMS.

GLOSSARY OF TERMS USED

-   TCP: Transmission Control Protocol-   IP: Internet Protocol-   HTTP: Hypertext Transfer Protocol-   WAP: Wireless Application Protocol-   WDP: WAP Wireless Datagram Protocol-   SSL: Secure Socket Layer-   JMS: Java Message Service (http://java.sun.com/products/jms/)-   PDA: Personal Digital Assistant-   SMS: Short Messaging Service-   GSM: Global System for Mobile Telecommunication-   DAB: Digital Audio Broadcast-   JDBC: Java Database Connectivity    (http://java.sun.com/products/jdbc/)-   ODBC: Microsoft's Open Database Connectivity-   MOM: Message Oriented Middleware

1. A method for delivering data between an application serving as clientand running on a mobile wireless device and a message orientedmiddleware application running on a computer of a wired network,comprising the steps of implementing, on the mobile wireless device, amessaging system Application Programming Interface (API); running amessage proxy on a computer connected to the wired network, the proxymaintaining client subscriptions to topics and queues, and receiving andforwarding messages; and at least one of the following two steps of theclient calling a command provided by the messaging system API; the proxyreceiving a message on behalf of the client; and further comprising thestep of the proxy acting towards the message oriented middleware onbehalf of the client as if the client was accessing the message orientedmiddleware directly.
 2. The method of claim 1, wherein a thin messageclient is installed on the mobile wireless device and implements the APIof the messaging system, comprising the steps of the client calling acommand provided by the thin message client API; a command subsystem ofthe thin message client creating a code information representing thecommand; sending the code information to the message proxy usingwireless communication; simultaneously or subsequently, transmittingmessage data to the message proxy; the message proxy maintaining messagesystem state information associated with the client; creating, by themessage proxy, at least one MOM command referred to by the codeinformation; and the message proxy forwarding the message data to themessage oriented middleware application, using said at least one MOMcommand.
 3. The method of claim 1, wherein a thin message client isinstalled on the mobile wireless device and implements the API of themessaging system, comprising the steps of the proxy receiving a messageon behalf of the client; the proxy creating a code informationrepresenting the message; the proxy sending the code information to thethin message client using wireless communication; the thin messageclient creating, from the code information, a message; and the clientprocessing the message.
 4. The method of claim 1, comprising the step ofat least one of the clients and the proxy storing messages in a localdatabase, such that they will not be lost when a client is disconnectedfrom the proxy.
 5. The method of claim 1, comprising the steps of themessage proxy starting, at runtime, a pluggable transport protocoladapter enabling communication over a given transport protocol; themessage proxy sending and receiving messages to and from message clientsby means of the transport protocol adapter, using wireless protocols. 6.The method of claim 5, wherein said at least one transport protocoladapter supports HTTP or SMS or WAP or WDP or GPRS or UMTS.
 7. Themethod of claim 2, wherein the command provided by the thin messageclient API and represented by code information or tokens is one of“subscribe”, “unsubscribe”, “create topic”, “publish”.
 8. The method ofclaim 1, wherein the API client library is a JMS (Java Messaging System)library.
 9. A system for delivering data between an application servingas client and running on a mobile wireless device and a message orientedmiddleware application running on a computer of a wired network,comprising a messaging system Application Programming Interface (API)implemented on the mobile wireless device; a message proxy implementedon a computer connected to the wired network, the proxy being configuredto maintain client subscriptions to topics and queues, and to receiveand forward messages; the proxy being configured to act towards themessage oriented middleware on behalf of the client as if the client wasaccessing the message oriented middleware directly; in at least one ofthe cases of the client calling a command provided by the messagingsystem API; the proxy receiving a message on behalf of the client. 10.The system of claim 9, wherein the message proxy comprises a wirelesstransport protocol adapter implemented before start-up of the messageproxy and a wireless transport protocol adapter implemented by a programcode at run-time of the message proxy.